A survey by questionnaire of 67 Japanese children affected by watching the animated television series Pocket Monsters (Pokemon) on December 16, 1997 and their parents was compared with that of children not affected by the program, in a study conducted at Showa University School of Medicine, Tokyo, Japan, and other centers. Children who visited 14 pediatric clinics for other reasons within 2 months after the incident were included. Of 1,373 replies, 800 were male and 558 female (15 unspecified), and mean age was 6.8 +/- 3.5 years. The majority (80%) had watched the program, and 67 (6.1%; 40 males, 27 females) were affected. Ten had photosensitive seizures (0.9%; 4 males and 6 females; mean age 10.8 years) and 57 developed other symptoms: a) during or immediately after, or b) at least 30 minutes after viewing the TV program. Older children tended to develop symptoms, including seizures, more frequently than younger children. Symptoms in Group a) included headache, nausea, vomiting, blurred vision or vertigo (28 children [2.6%]), and delayed-onset symptoms in Group b) were similar or minor, resembling motion sickness (29[2.7% of viewers]). Individual or family history of seizures was obtained in 80% patients with seizures, compared to only 29% of patients with other symptoms and 27% with minor delayed-onset symptoms (p<0.001). Compared with nonaffected children, significantly more affected children had concentrated on watching the TV program, watched it at a short distance from the screen, and in a dimly lit room. 
COMMENT. Pokemon phenomenon was a significant social problem in Japan and resulted in many studies regarding the adverse effects of cathode ray tube images and TV viewing, conditions facilitating induction of photosensitive seizures, and other symptoms. Children with seizures had a heightened predisposition, and viewing conditions had not been optimal. Guidelines for TV viewers cautioned against sitting close to the screen and in a dark room. Blue sunglasses were recommended for viewers susceptible to photosensitive epilepsy. Symptoms occurring other than seizures included headache and dizziness, resembling motion sickness. See Progress in Pediatric Neurology III, PNB Publishers, 1997;pp 64-67, for articles on visually induced seizures, including video-game epilepsy, self-induced photogenic epilepsy, and reading epilepsy.